Copper-Modified Nanocarbon Composites for Enhanced Hydrogen Sulfide Adsorption: Synergistic Effects of Persistent Free Radicals and Cu-Based Oxides.

In this study, copper-modified nanocarbon composites (OMC) were successfully prepared using two-dimensional carbon nanosheets as the material substrate, the low-temperature hydrothermal method as the main process, and copper nitrate as the modifier. The effects of the modifier dosage ratio, hydrothermal temperature, and residence time on the structure and hydrogen sulfide (HS) adsorption performance of OMC were investigated. The results show that the OMC with persistent free radicals and copper oxides prepared under the conditions of a mass ratio of copper nitrate to two-dimensional carbon nanosheets of 2, a hydrothermal temperature of 130 °C, and a time of 8 h, respectively, has the best adsorption performance for HS, with an adsorption sulfur capacity of up to 46.72 mg/g. The excellent adsorption and removal capacity of the OMC for HS are attributed to two reasons. First, the addition of copper during the hydrothermal process promotes the generation of persistent free radicals on the surface of OMC, enhancing its oxidation capacity for HS. Second, the copper oxide loaded on the surface of OMC also has a good adsorption capacity for HS. The synergistic effect of persistent free radicals and copper oxides converts HS into solid products such as sulfides, elemental sulfur, sulfites, and sulfates. This work not only achieved the goal of low-temperature preparation of nanocarbon composites but also expanded the application of persistent free radicals in pollutant control.